INSTRUCTOR’S GUIDE
Course: Auxiliary Engines
Topic: Basic Cooling System in a Marine
Diesel Engine
ILOs: At the end of this session, the
participants shall be able to:
1. explain the importance of cooling
system in a marine diesel engine;
2. differentiate freshwater and seawater
cooling system in a marine engine; and
3. show how engine cooling system works
through a diagram.
What do they have in common?
What is an Engine Cooling System?
System installed to keep the
temperature of an engine from
exceeding limits imposed by needs
of safety and efficiency.
Importance of Cooling System in Marine Diesel Engine
1.Sea Water cooling system: Seawater is
directly used in the machinery systems as a
cooling media for heat exchangers.
Types of 2.Freshwater or central cooling
Cooling System system: Freshwater is used in a closed circuit
to cool down the engine room machinery.
Onboard Ships The freshwater returning from the heat
exchanger after cooling the machinery is
further cooled by seawater in a sea-water
cooler.
Three (3) Main Components of Seawater
Cooling System
- Seawater Pump
- Heat Exchangers
- Overboard Valves
Freshwater Cooling System Circuits
High-Temperature Circuit
Low-Temperature Circuit
Seawater Circuit
Seawater and freshwater cooling diagram
Always Remember…………………
References
• https://weberautomotive.com/the-importance-o
f-cooling-system-maintenance
• https://jblcfmarpower.wordpress.com/topic-1-ilo
-describe-the-engine-cooling-water-systems/
• https://seamankowts.net/how-do-seawater-and-
freshwater-cooling-systems-on-ships-work/
